1. Field of the Invention
The present invention relates to the over-ride of a driver demand in a motor vehicle, particularly when the driver activates at the same time both the brake pedal and the accelerator pedal.
2. Related Art
A motor vehicle driver controls the speed of a conventional vehicle using foot pedals, which in a vehicle with an automatic transmission are the accelerator pedal and brake pedal and, in a vehicle with a manual transmission, also the clutch pedal. Drivers will normally use the same foot to control both the accelerator pedal and the brake pedal.
However, some drivers of automatic transmission vehicles use two feet, one to control the accelerator pedal and the other to control the brake pedal. This can result in simultaneous activation of both the vehicle brake and accelerator, which can result in brake overheating or undue wear, as well as causing a potential safety problem owing to constant activation of the brake lights when the vehicle is actually not slowing down. As a result it has been proposed to monitor the brake and accelerator pedals to detect simultaneous operation of both these pedals and to reduce or cut the driver demand to the engine when simultaneous operation has been detected.
The present inventors have realized, however, that there are times when the driver may be activating both pedals at the same time in such a way that would not give rise to the aforementioned problems of brake wear or brake light safety. For example, there is a style of sport driving in manual transmission vehicles called “heal-toe” driving, in which the driver when braking with one foot and activating the clutch with the other foot for a gear change, also uses the one foot to rev the engine above its idle speed. This may be necessary in off-road rally driving to avoid slippage of the driving wheel when a lower gear is activated.
Another situation in which simultaneous activation of the brake and accelerator may be acceptable is when a two-footed driver lightly rests one foot on the accelerator while using the other foot to brake the vehicle. The driver demand may cause the engine speed to rise above the idle speed, but there may be no problem as long as the engine speed remains within acceptable limits and as long as there is no unequal braking of the wheels.